Iontophoresis can by defined a the application of drugs or medications in their ionic forms to the surface of tissues, e.g. to the surface of the skin. An electric current of relatively low amplitude level, as obtained from a voltage having a selected polarity which is opposite to the polarity of charge of the drug ions, is passed through the drug and the body area of the patient into which the drug is to be introduced thereby driving the oppositely charged drug ions transdermally through the skin tissue.
In applying such technique to a patient, an electrode which contains the medication to be introduced is normally positioned over the region of the body which is to be treated and a second electrode, which normally contains a conductive gel, but no medication, is placed at the region of the patient's body opposite thereto so as to form an electric circuit with the current source for the system. Application of a current producing voltage across the electrodes provides desired operating current for causing the ionized molecules of the medication to be transported transdermally into the body portion where the medication can produce its therapeutic effects.
While iontophoresis is a method of administering drugs has been known or many years, little effective use has been made of the technique because the systems purporting to utilize such methods have been too cumbersome, inefficient, and/or costly to find a ready market for them. Moreover, such systems do not permit effective control of the drug delivery rate or provide any effective safety control for the current level which is used. Further, there tends to be a resistance to the use thereof by some patients who may experience traumatic effects from the actual or anticipated use thereof.
It is desirable that an effective system by devised in which the application of the drug dose and the rate at which such dosage is applied can be readily controlled and in which the probability of high patient drug compliance is increased. Such a system should be one designed so as to provide the desired operation at a reasonable cost and one which can be easily used by a doctor, nurse, or even the patient himself or herself, without fear of harm, of making a mistake, or of causing the system to become inoperative.